This invention relates to acoustic loudspeaker systems, and more particularly to a loudspeaker cabinet having reed baffles providing control over the resonance, air and mass created by loudspeakers mounted within the cabinet to clearly and accurately reproduce amplified input sound signals over a broad audio frequency range, thereby providing a wider bass range while providing a natural sound.
A loudspeaker cabinet enclosure serves to dampen the speakers mounted therein as well as to provide a means for preventing phase cancellation, particularly low frequency cancellation. A properly tuned enclosure will reduce "hangover" i.e., out of phase waves from the rear of the speaker cone mixing with and thereby cancelling the front wave, and improves the transient response. The cabinet or enclosure also has its own natural frequency at which it resonates, providing a larger vibrating air mass increasing bass output.
While there are a large number of loudspeaker systems in the prior art capable of high quality sound, most are deficient in producing a natural bass sound. This deficiency appears to be due to an ineffective matching between the speaker elements and the cabinet enclosure in which they are mounted. The result is a dramatic degradation of the systems dynamic range, and its ability to reproduce natural sound through the bass e.g. 20 Hz to 1 kHz range, and critical midrange frequency e.g. 1 kHz to 60 kHz range.
The most vital factor in reproducing a "clean" vibrant sound is the transient response of the speaker system. Transient response is the speaker's ability to instantaneously react to the input from an amplifier, i.e., the reaction time for the speaker to respond to electrical pulses to make sound. Although larger bass speakers or woofers generally provide a lower frequency bass response than small woofers because of the larger air mass set into vibration, they generally have a degraded transient response because the larger mass of air has a greater inertia and requires a greater amount of time to cease vibrating or oscillating after the input signal has terminated.
Speaker enclosures are generally of either the acoustic suspension type, wherein the enclosure is effectively air tight, and the ported reflex type wherein a small hole is cut into the enclosure with a tube or duct disposed within the hole to act as a partial vent for the compressing and decompressing air. In the ported reflex type, low frequency air vibrations within the port are out of phase with speaker cone motion, thereby providing a greater damping cushion to cone motion. The large volume of air through the port produces increased bass output. As the air within the enclosure is compressed and decompressed at the low frequencies, the air moves through the port. But since proper tuning is difficult to obtain, many prior art ported reflex speaker systems provide an unnatural base sound reproduction.
Additionally, although conventional speaker systems are efficient at the natural or resonance frequency of the cabinet, their efficiency degrades in other frequency ranges. Almost invariably, except for exceptionally large cabinet enclosures used with very expensive systems, the response graph of a speaker system designed to have relatively low bass response has multiple peaks and dips at the midrange frequencies, and those having reasonable flat midrange responses have poor bass response falling off drastically somewhere approximately 80 Hz. A smooth, flat response, however is more desirable than a wide range with multiple peaks and dips. For example a speaker system with a flat response from 80 Hz to 12,000 Hz can reproduce music more accurately than a speaker with a response of 30 Hz to 18,000 Hz with a sporadic response curve. The most desirable response, of course, is that which reproduces the clarity and natural sound of "live" music.